pkg/machine/compression: skip decompress bar for empty file

When the file is empty it is possible our code panics as bar.ProxyReader
returns nil when the bar is finished which is the case for 0 size as it
doesn't have to read anything from there. However as this happens on
different goroutines it is race and most of the time still works.

To fix this simply skip the progress bar setup for empty files.

While at it fix the deprecated argument in the tests.

Fixes #23281

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

pkg/machine/compression/decompress.go

@@ -66,18 +66,27 @@ func runDecompression(d decompressor, decompressedFilePath string) (retErr error
 	}
 	defer d.close()
 
-	initMsg := progressBarPrefix + ": " + filepath.Base(decompressedFilePath)
-	finalMsg := initMsg + ": done"
+	filesize := d.compressedFileSize()
+	// bar.ProxyReader() returns nil when the bar is finished.
+	// When the size is set to 0 the bar will finfish immediately, but this happens
+	// in a different goroutine so it is race and only happens sometimes.
+	// In general if the input is an empty file then we do not have to display a
+	// progress bar at all as there is nothing to copy/extract really
+	// https://github.com/containers/podman/issues/23281
+	if filesize > 0 {
+		initMsg := progressBarPrefix + ": " + filepath.Base(decompressedFilePath)
+		finalMsg := initMsg + ": done"
 
-	p, bar := utils.ProgressBar(initMsg, d.compressedFileSize(), finalMsg)
-	// Wait for bars to complete and then shut down the bars container
-	defer p.Wait()
+		p, bar := utils.ProgressBar(initMsg, filesize, finalMsg)
+		// Wait for bars to complete and then shut down the bars container
+		defer p.Wait()
 
-	compressedFileReaderProxy := bar.ProxyReader(compressedFileReader)
-	// Interrupts the bar goroutine. It's important that
-	// bar.Abort(false) is called before p.Wait(), otherwise
-	// can hang.
-	defer bar.Abort(false)
+		compressedFileReader = bar.ProxyReader(compressedFileReader)
+		// Interrupts the bar goroutine. It's important that
+		// bar.Abort(false) is called before p.Wait(), otherwise
+		// can hang.
+		defer bar.Abort(false)
+	}
 
 	var decompressedFileWriter *os.File
 
@@ -94,7 +103,7 @@ func runDecompression(d decompressor, decompressedFilePath string) (retErr error
 		}
 	}()
 
-	if err = d.decompress(decompressedFileWriter, compressedFileReaderProxy); err != nil {
+	if err = d.decompress(decompressedFileWriter, compressedFileReader); err != nil {
 		logrus.Errorf("Error extracting compressed file: %q", err)
 		return err
 	}

test/system/610-format.bats

@@ -149,7 +149,7 @@ function check_subcommand() {
     # ...or machine. But podman machine is ultra-finicky, it fails as root
     # or if qemu is missing. Instead of checking for all the possible ways
     # to skip it, just try running init. If it works, we can test it.
-    run_podman '?' machine init --image-path=/dev/null mymachine
+    run_podman '?' machine init --image=/dev/null mymachine
     if [[ $status -eq 0 ]]; then
         can_run_podman_machine=true
         extra_args_table+="